/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996-1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>
#include <string.h>

#if defined(_MSC_VER) && _MSC_VER < 1600
#include "stdint-msvc2008.h"
#else
#include <stdint.h>
#endif

#include "uv.h"
#include "uv-common.h"

#define UV__INET_ADDRSTRLEN 16
#define UV__INET6_ADDRSTRLEN 46

static int inet_ntop4(const unsigned char* src, char* dst, size_t size);
static int inet_ntop6(const unsigned char* src, char* dst, size_t size);
static int inet_pton4(const char* src, unsigned char* dst);
static int inet_pton6(const char* src, unsigned char* dst);

int uv_inet_ntop(int af, const void* src, char* dst, size_t size)
{
    switch (af) {
    case AF_INET:
        return (inet_ntop4(src, dst, size));
    case AF_INET6:
        return (inet_ntop6(src, dst, size));
    default:
        return UV_EAFNOSUPPORT;
    }
    /* NOTREACHED */
}

static int inet_ntop4(const unsigned char* src, char* dst, size_t size)
{
    static const char fmt[] = "%u.%u.%u.%u";
    char tmp[UV__INET_ADDRSTRLEN];
    int l;

    l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);
    if (l <= 0 || (size_t)l >= size) {
        return UV_ENOSPC;
    }
    strncpy(dst, tmp, size);
    dst[size - 1] = '\0';
    return 0;
}

static int inet_ntop6(const unsigned char* src, char* dst, size_t size)
{
    /*
   * Note that int32_t and int16_t need only be "at least" large enough
   * to contain a value of the specified size.  On some systems, like
   * Crays, there is no such thing as an integer variable with 16 bits.
   * Keep this in mind if you think this function should have been coded
   * to use pointer overlays.  All the world's not a VAX.
   */
    char tmp[UV__INET6_ADDRSTRLEN], *tp;
    struct {
        int base, len;
    } best, cur;
    unsigned int words[sizeof(struct in6_addr) / sizeof(uint16_t)];
    int i;

    /*
   * Preprocess:
   *  Copy the input (bytewise) array into a wordwise array.
   *  Find the longest run of 0x00's in src[] for :: shorthanding.
   */
    memset(words, '\0', sizeof words);
    for (i = 0; i < (int)sizeof(struct in6_addr); i++)
        words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));
    best.base = -1;
    best.len = 0;
    cur.base = -1;
    cur.len = 0;
    for (i = 0; i < (int)ARRAY_SIZE(words); i++) {
        if (words[i] == 0) {
            if (cur.base == -1)
                cur.base = i, cur.len = 1;
            else
                cur.len++;
        } else {
            if (cur.base != -1) {
                if (best.base == -1 || cur.len > best.len)
                    best = cur;
                cur.base = -1;
            }
        }
    }
    if (cur.base != -1) {
        if (best.base == -1 || cur.len > best.len)
            best = cur;
    }
    if (best.base != -1 && best.len < 2)
        best.base = -1;

    /*
   * Format the result.
   */
    tp = tmp;
    for (i = 0; i < (int)ARRAY_SIZE(words); i++) {
        /* Are we inside the best run of 0x00's? */
        if (best.base != -1 && i >= best.base && i < (best.base + best.len)) {
            if (i == best.base)
                *tp++ = ':';
            continue;
        }
        /* Are we following an initial run of 0x00s or any real hex? */
        if (i != 0)
            *tp++ = ':';
        /* Is this address an encapsulated IPv4? */
        if (i == 6 && best.base == 0 && (best.len == 6 || (best.len == 7 && words[7] != 0x0001) || (best.len == 5 && words[5] == 0xffff))) {
            int err = inet_ntop4(src + 12, tp, sizeof tmp - (tp - tmp));
            if (err)
                return err;
            tp += strlen(tp);
            break;
        }
        tp += sprintf(tp, "%x", words[i]);
    }
    /* Was it a trailing run of 0x00's? */
    if (best.base != -1 && (best.base + best.len) == ARRAY_SIZE(words))
        *tp++ = ':';
    *tp++ = '\0';

    /*
   * Check for overflow, copy, and we're done.
   */
    if ((size_t)(tp - tmp) > size) {
        return UV_ENOSPC;
    }
    strcpy(dst, tmp);
    return 0;
}

int uv_inet_pton(int af, const char* src, void* dst)
{
    if (src == NULL || dst == NULL)
        return UV_EINVAL;

    switch (af) {
    case AF_INET:
        return (inet_pton4(src, dst));
    case AF_INET6: {
        int len;
        char tmp[UV__INET6_ADDRSTRLEN], *s, *p;
        s = (char*)src;
        p = strchr(src, '%');
        if (p != NULL) {
            s = tmp;
            len = p - src;
            if (len > UV__INET6_ADDRSTRLEN - 1)
                return UV_EINVAL;
            memcpy(s, src, len);
            s[len] = '\0';
        }
        return inet_pton6(s, dst);
    }
    default:
        return UV_EAFNOSUPPORT;
    }
    /* NOTREACHED */
}

static int inet_pton4(const char* src, unsigned char* dst)
{
    static const char digits[] = "0123456789";
    int saw_digit, octets, ch;
    unsigned char tmp[sizeof(struct in_addr)], *tp;

    saw_digit = 0;
    octets = 0;
    *(tp = tmp) = 0;
    while ((ch = *src++) != '\0') {
        const char* pch;

        if ((pch = strchr(digits, ch)) != NULL) {
            unsigned int nw = *tp * 10 + (pch - digits);

            if (saw_digit && *tp == 0)
                return UV_EINVAL;
            if (nw > 255)
                return UV_EINVAL;
            *tp = nw;
            if (!saw_digit) {
                if (++octets > 4)
                    return UV_EINVAL;
                saw_digit = 1;
            }
        } else if (ch == '.' && saw_digit) {
            if (octets == 4)
                return UV_EINVAL;
            *++tp = 0;
            saw_digit = 0;
        } else
            return UV_EINVAL;
    }
    if (octets < 4)
        return UV_EINVAL;
    memcpy(dst, tmp, sizeof(struct in_addr));
    return 0;
}

static int inet_pton6(const char* src, unsigned char* dst)
{
    static const char xdigits_l[] = "0123456789abcdef",
                      xdigits_u[] = "0123456789ABCDEF";
    unsigned char tmp[sizeof(struct in6_addr)], *tp, *endp, *colonp;
    const char *xdigits, *curtok;
    int ch, seen_xdigits;
    unsigned int val;

    memset((tp = tmp), '\0', sizeof tmp);
    endp = tp + sizeof tmp;
    colonp = NULL;
    /* Leading :: requires some special handling. */
    if (*src == ':')
        if (*++src != ':')
            return UV_EINVAL;
    curtok = src;
    seen_xdigits = 0;
    val = 0;
    while ((ch = *src++) != '\0') {
        const char* pch;

        if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
            pch = strchr((xdigits = xdigits_u), ch);
        if (pch != NULL) {
            val <<= 4;
            val |= (pch - xdigits);
            if (++seen_xdigits > 4)
                return UV_EINVAL;
            continue;
        }
        if (ch == ':') {
            curtok = src;
            if (!seen_xdigits) {
                if (colonp)
                    return UV_EINVAL;
                colonp = tp;
                continue;
            } else if (*src == '\0') {
                return UV_EINVAL;
            }
            if (tp + sizeof(uint16_t) > endp)
                return UV_EINVAL;
            *tp++ = (unsigned char)(val >> 8) & 0xff;
            *tp++ = (unsigned char)val & 0xff;
            seen_xdigits = 0;
            val = 0;
            continue;
        }
        if (ch == '.' && ((tp + sizeof(struct in_addr)) <= endp)) {
            int err = inet_pton4(curtok, tp);
            if (err == 0) {
                tp += sizeof(struct in_addr);
                seen_xdigits = 0;
                break; /*%< '\\0' was seen by inet_pton4(). */
            }
        }
        return UV_EINVAL;
    }
    if (seen_xdigits) {
        if (tp + sizeof(uint16_t) > endp)
            return UV_EINVAL;
        *tp++ = (unsigned char)(val >> 8) & 0xff;
        *tp++ = (unsigned char)val & 0xff;
    }
    if (colonp != NULL) {
        /*
     * Since some memmove()'s erroneously fail to handle
     * overlapping regions, we'll do the shift by hand.
     */
        const int n = tp - colonp;
        int i;

        if (tp == endp)
            return UV_EINVAL;
        for (i = 1; i <= n; i++) {
            endp[-i] = colonp[n - i];
            colonp[n - i] = 0;
        }
        tp = endp;
    }
    if (tp != endp)
        return UV_EINVAL;
    memcpy(dst, tmp, sizeof tmp);
    return 0;
}
